Description: This study reveals that the nature of the instructions given before national evaluation exercises are done may modulate pupils' performances according to their gender. Indeed, we think that the conditions in which national evaluations are taken put all the pupils under great pressure, and some might experience the 'stereotype threat' phenomenon when, for example, the girls are evaluated in maths tests or, conversely, when boys' academic levels are evaluated in French. The analysis of our results shows that the most decisive element in these contexts seems well to be the weight of the pressure of evaluation. Whether this pressure is explicit or implicit, it seems to have very negative effects on pupils who usually fail in such situations. These first very encouraging results will have however to be retorted before being generalized